Improvement in scroll-sawing machines



wlLLlAM H. noAN E.

Improvement in Scrpll-Sawing Machines.

Patented May28, T872.

INVENT 0R 'UNITED STATES PATENT OFFICE,

WILLIAM H. DOANE, OF CINCINNATI, OHIO, ASSIGNOR TO J. A. FAY

' 86 COMPANY, OF SAME PLACE.

IMPROVEMENT IN SCROLL-SAWING MACHINES.

Specification forming part of Letters Patent No. 127,225, dated May 28,1872.

I, WILLIAM H. DOANE, of the city of Cincinnati, `in the county ofHamilton and State of Ohio, have invented certain new and use- In theaccompanying' drawing- Figure l is an elevation in -perspective of thefront, top, and one side of that portion of a scroll-saw which is abovethe. table, and which embodies my improvements. Fig. 2 is a verticalsection of the same portion of said scroll-saw from front to rearthrough the center of Fig. l. Fig. 3 is a transverse plan section ofFig. l, made at the set-screw R, of Fig. 1.

General Description.

A is the upright which supports the machinery for the scroll-saw. B isthe frame adjustable upon upright A and supporting all the uppermechanism of the saw. A shoulder or arm, B, projects forward from theupper part of B and supports the bow C at its middle. J and J are slotsthrough the upright A. Slot J is opposite the upper'part of frame B.Slot J is opposite the lower part of said frame. A bolt, V, connected atone end with frame B, passes through the slot J The other end of thisbolt extends beyond the back of the upright and has a screw -thread cutupon it, upon which is a nut and washer. 'This bolt is of such a sizethat it will slide up or down from the top to the bottom of slot Jwithout obstruction. V, a bolt similar to bolt V, passes through slot Jand has a nut and washer on its rear end. Bolt V' slides up and down inslot J as bolt V does in slot J. The middle of the bow-springs its intoa recess in the front of shoulder D and is held there by a plate, D, and`screw D. The ends of the bow C are enlarged and in each of them is alongitudinal vertical slit, H. Transversely through each of said ends ascrew, F, passes. Each screw enables the slit through which it crossesto be opened or closed at will. E is the bowcord or string passing fromthe bottom side of one end of the bow up through the slit H, over anddown around the screw F,` then through the eyelet of K across to theother end of the bow, where at H said cord is similarly secured. O isthe saw-guide tting between two langes, L L, projecting from the frontof frame B and pivotcd on the upper front corner of said anges at a. Qis a handle attached to the lower part of the side of O for adjustingsaid guide and giving it a proper inclined position. R is a set-screw inone of the flanges L, for the purpose of holdin g the guide at anydesired inclined position. P is a piece of steel or hard metal setvertic- -ally into the middle of the front of the guide, and aording aproper bearing for the T-head b. M M are guides, one on each side of theT-head and over the front edges of these sides, thus holding down saidT-head and guiding it by their inwardly enlarging beveled sides. T is ashaft sliding up into the bottom of frame B and provided at its lowerend with a foot, S, for holding down the timber while being sawed. d isa set-screw for holding t-he shaft T and foot S at any required height.N'is a ratchet on the middle of the rear side of the adjustable-frame B.X is a pinion pivoted within the upright A and toothed into the ratchetN. Z is a lever on the outside of the upright A for turning the lpinionX. K is a rod jointed if desired at itsmiddle, as shown in Fig. 1. K,near its lower end, is attached to the front of T-head b. The lower endof K curves out from the T-head in a segment of a circle and is piercedwith a longitudinal slot for the entrance of the head of the saw. In theupper end of K is an eye through which passes the cord of thebow-spring. This cord is usually covered with leather or buckskin or thelike within the eye, 4to prevent its abrasion by said eye.

Mode ,of Operation.

The mode in which a machine for scroll-sawing, having my aforesaidimprovements applied to it, operates, is as follows: The head of ascroll-saw of the proper dimensions is passed up through the slot in thelower end of K, and a bolt or key is then passed through the head ofsaid saw above the slot and at right angles to it. The said saw is thenproperly attached below. The office of the bow is to draw up the sawafter each downward stroke. If the tension of the bow-cord E is toogreat or too little the difficulty can be remedied by unscrewing thescrew F and letting out or tightening up the cord, by passing it up ordown through slit H and then tightening the screws F F. To give a properrake or inclination to the cord take hold of lever Q and draw out thebottom of the guide 0 until the requisite inclination of the guide isobtained. The set-screw B is then tightened and thereby the guide isheld in the desired position.

The T-head, usually of steel, slides upon the steel-bearingP; thisbearing is very durable. When worn out it can be easily replaced byanother, it being held in position by the guides M M. Whenever the sawbreaks oli' near either end, the saw is not useless. It can be usedagain by boring a new hole in it near Where it was broken off, and thenresetting it in the machine. It will be just as much shorter, however,as the short piece broken off detracts from the original length of thesaw.

The adjustment of the connecting-rod K and the whole of the uppermachinery to the shortened saw is accomplished by unscrewing the nutsupon the bolts V and V and turning the lever Z and pinion X so as todepress sufficiently the frame B. This adjustment being made the screwsV and Vl are again tightened. In tightening they draw the frame B hardagainst upright A; said upright is thus grasped lirmly in front by frameB and behind by said nuts, and the said frame B is thus secured inposition. The broken saw is again ready for operation.

Claims.

What I claim as new, is-

1. A bow-spring for raising a scroll-sawk

